Biocatalysis with Undissolved Solid Substrates and Products

Biocatalysis with Undissolved Solid Substrates and Products 

Alessandro Basso, Sara Contone, Cynthia Ebert, PeterJ. Hailing and Lucia Cardossi 

Catalysis in reaction systems with undissolved substrates and products is not restricted to biocatalysis. High yields in sobd-state synthesis, sohd-to-sohd reactions, and solvent-free systems have also been reported for aldol condensation, Baeyer-Villiger oxidation, oxidative coupling of naphthols, and condensation of amines and aldehydes [1, 2]. 

The study of enzymatic reactions in systems with substrates present at very high mass/volume ratios, often leading to suspensions rather than solutions, has also been pursued. The majority of the published work on this type of reaction was related to the synthesis of protected peptides [3-15], but the synthesis of beta-lactam antibiotics [16-19], glycosides [20, 21], glycamides [22], and esters [23-27] starting from suspended substrates has also been reported. 

Enzymatic synthesis in reaction mixtures with mainly undissolved substrates and/or products is a synthetic strategy in which the compounds are present mostly as pure solids [28, 29]. It retains the main advantages of conventional enzymatic synthesis such as high regio- and stereoselectivity, absence of racemization, and reduced side-chain protection. When product precipitates, the reaction yields are improved, so that the necessity to use organic solvents to shift the thermodynamic equilibrium toward synthesis is reduced and synthesis is made favorable even in water. 

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Biocatalysis with Undissolved Solid Substrates and Products Synthesis of cephalosporins... 

Ulijn, R,V., De Martin, L., Gardossi L. and Hailing, P.J., Biocatalysis in reaction mixtures with undissolved solid substrates and products. Curr. Org. Chem., 2003, 7, 1333-1346. 

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